METHOD FOR RADIATION THERAPY DELIVERY AT VARYING SOURCE TO TARGET DISTANCES

摘要

A method for providing radiation therapy to target tissue in a patient provides for adjustment of the vertical position of the patient couch to account for errors introduced by the weight supported by the couch at its desired positions for treatment The method further contemplates determining the initial location of the center of the target tissue with respect to the immobilization frame supporting the patient, to eliminate errors introduced by collateral position sensing equipment. The method is particularly suited for extended distance treatments wherein, in one embodiment, a tare is established based on the actual isocenter of the gantry and then a subsequent adjustment of couch position is made with respect to movement of the couch to position the target tissue at the virtual isocenter.